Image capturing devices, such as cameras, tend to have a lens that focuses an image on an image sensor, such as film or a charge coupled device (CCD). Lens distortions, called aberrations, limit the sharpness of the image formed by the lens. Aberrations can be grouped into two general types: those that are caused by design compromises of a lens model or specification; and those that are caused by deviations from the lens model when individual lenses are made. These aberrations can decrease image quality even if the lens is perfectly focused.